Abstract
1. The study was made on the behavior of serum and urine ribonucleaae (RNase) during the clinical course of various diseases including cancer of the digestive organs and other non-malignant diseases.
2. Serum and urine RNase activity was significantly decreased during the entire course of therapeutic X-ray irradiation to the human subject which followed radical resection of carcinoma of the breast or rectum. Inoperable cancer patients responded to the irradiation with variable activities. Those inoperable with clinical improvement, however, showed some decrease of RNase levels during this period.
3. In patients with cancer of the stomach and breast, postoperative chemotherapy resulted in a marked decline in RNase activity compared with control values. Tumorbearing patients also showed a decreasing tendency in enzyme activity following this therapy, but this effect did not last beyond the period of 5 or 6 weeks of chemotherapy.
4. The incidence of serum RNase elevations was significantly higher in patients with impaired hepatic function than in those with normal liver function. In general, there was a considerable correlation between the blood RNase level and the activity of whole liver homogenate obtained at laparotomy in 24 patients with malignant and non-malignant diseases.
5. Mild to moderate RNase elevations were observed in many patients with marked hypoproteinemia as well as in those with depressed albuminglobulin ratio, and the enzyme activity usually rose to higher levels as this value decreased. The blood RNase activity was also extremely raised in patients with raised serum urea nitrogen.
6. There was little correlation between the serum RNase level and the serum LDH activity, although RNase elevations were found in half of the patients with increased LDH values. The high incidence of serum RNase elevations in patients with hepatobiliary diseases appeared to be comparable to the frequency of elevations in the serum LAP activity of the same patients.
